The present invention relates to a reclining mechanism for an automotive seat having a bracket for providing a spiral spring therearound.
Conventionally, in a reclining seat mechanism for a vehicle there is provided a tilting angle adjusting mechanism for adjusting the tilting angle of an upper arm to be secured to a seat back frame with respect to a lower arm to be secured to a seat cushion frame. Usually, the tilting angle adjusting mechanism is composed of a combination of pawl teeth and a ratchet or a reduction gear set using a planetary gear. In any case, in the course of the seat back frame being folded forwardly, a spiral spring of which one end is engaged with the upper arm and the other end is engaged with a stationary member of the lower arm will urge the upper arm in a forwardly folded direction.
The disclosure of Japanese Utility Model Laid Open (KOKAI) Publication No. 169149/1989 proposes a reclining seat mechanism for a vehicle having a bracket of L-shape with which a spiral spring is engaged. The other end of the spiral spring is engaged with a rotatable shaft for interlocking a lower arm to be secured to a seat cushion frame and an upper arm to be secured to a seat back frame, or a pin coaxially arranged with an axis of the rotatable shaft. The attachment of the bracket to the upper arm becomes larger in a structure of the upper arm and the engagement of the spiral spring with the rotatable shaft contributes to the injury of the rotatable shaft.
It is therefore an object of the present invention to provide a reclining mechanism for an automotive seat having a bracket with a pair of opposed projections axially extending from a base thereof.
Another object of the present invention is to provide a reclining mechanism for an automotive seat which performs a play-free arrangement of a spiral spring for urging an upper arm in a forward direction.
To achieve these objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the reclining mechanism of this invention comprises a lower arm to be secured to a seat cushion frame, an upper arm to be secured to a seat back frame, a rotatable shaft passing through both arms and supporting a manipulating lever having a cam hole, a cam member fixedly secured on the rotatable shaft and positioned inside of protuberances on both arms, a pawl plate having pawl teeth at one end which are engaged with or disengaged from a toothed zone formed on a part of an inner side wall of the protuberance of the upper arm, and further having a pin passing through the cam hole of the manipulating lever, a bracket supported on the rotatable shaft and having a pair of opposed projections, a spiral spring provided around the bracket, one end thereof being engaged with one of the projections and the other end thereof being engaged with the upper arm, and the inner diametrical coiled portion of the spiral spring being wound on outer surfaces of the projections.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.